Algae Resistant Polymer Granules for Asphalt Shingles

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Solution Overview

Problem

Conventional asphalt roofing materials with metallic granules for algae resistance are expensive and have a high metal leaching rate, leading to a shorter effective duration due to the surface presence of metals, which leach out quickly.

Innovation Solution

Development of polymer-based granules with a polyolefin carrier, functional additives like algaecides, and fillers, where the filler's median particle size and UV blocking agents are optimized to achieve a controlled leach rate of less than 100 ppm after 3000 hours, reducing the need for expensive metals and extending the effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic granules are used for algae resistance, then algae resistance is improved, but cost increases and metal leaching rate increases

Engineering Contradiction:

Improvealgae resistanceVSAvoidmetal leaching rate

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces expensive metallic granules with polymer-based granules containing organic biocides and algaecides. These polymer granules provide effective algae resistance without the high cost and excessive leaching rates of metallic alternatives, using organic compounds embedded in a polymer matrix that releases active ingredients at controlled rates.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates composite polymer granules by combining polymer materials with functional additives (biocides and algaecides). This composite structure integrates the protective function into the granule itself, allowing sustained release of active ingredients while maintaining structural integrity and reducing overall material cost compared to pure metallic granules.

Inventive Principle:

Principle #40Composite materials

2Reliability

If metallic granules are used for algae resistance, then algae resistance is improved, but effectiveness duration decreases

Engineering Contradiction:

Improvealgae resistanceVSAvoideffectiveness duration

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent achieves continuous algae resistance by embedding biocides and algaecides within the polymer granule matrix, enabling sustained release of active ingredients over time. This continuous action mechanism ensures prolonged effectiveness compared to metallic granules that leach rapidly and lose efficacy sooner.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent modifies the release parameters of the active ingredients by controlling the polymer matrix composition and structure. This allows regulation of the leach rate to optimize effectiveness duration, ensuring that biocides and algaecides are released at rates that maintain protective levels over extended periods without the rapid depletion seen with metallic granules.

Inventive Principle:

Principle #35Parameter changes

3Loss of substance

If polymer-based granules with controlled leach rate are used, then cost is reduced and effectiveness duration is extended, but manufacturing complexity increases

Engineering Contradiction:

Improvefunctional additive leach rateVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The patent controls the leach rate of functional additives by adjusting polymer composition, additive concentration, and granule structure parameters. By optimizing these parameters within established ranges, the formulation achieves targeted leach rates (e.g., less than 100 ppm after 3000 hours) using conventional manufacturing processes, avoiding excessive complexity while meeting performance specifications.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The polymer-based granules provide sustained resistance to algae and microorganisms with a balanced leach rate, reducing costs and maintaining effectiveness over a longer period compared to conventional metallic granules.

Implementation Method 1

from 0.25 wt. % to 5 wt. % of a UV blocking agent

Methodology Applied

Scientific EffectUV absorption: Absorption (EM radiation)

Implementation Method 2

The polymer-based granules leach less than 100 ppm of functional additive per gram of the polymer-based granule after 3000 hours of aging

Methodology Applied

Scientific EffectLeaching: Diffusion

Data Source

PatentUS20250019501A1Algae resistant polymer-based granules for asphalt shingles

Publication Date: 2025.01.16 OWENS CORNING INTELLECTUAL CAPITAL LLC

AI summary

Various embodiments described herein are directed algae resistant polymer-based granules and uses thereof. In various embodiments presented herein, the polymer-based granules include an algaecide, a biocide, a fungicide, an antimicrobial compound, or a mixture thereof in combination with a polymer carrier and, optionally, a filler. The resultant polymer-based granules include a precise balance between polymer carrier, filler, and functional additive to achieve a particular leach rate of the functional additive after 3000 hours of aging according to ASTM D4798.